Coconut retting method



Patented Mar. 9, 1943 rear orslcs 7 OOOONUT BETTING METHOD I Bernard Maisant, Paris, France; vested in the Alien Property Custodian No Drawing. Application April 10, 1939, Serial No. 267,203. In France July 21, 1938 4 Claims.

The present invention relates to the retting of coconut in an aqueous medium.

Numerous researches have been mad to improve the standard process consisting in leaving the coconuts to soak for several months in stagnant water; it has been proposed to boil the fibres in alkaline solutions or with an emulsion of linseed oil, to boil them in a closed vessel with an alkaline solution to which a mixture of alcohol and naphthenic acid has been added, to treat them first with a hot alkaline solution, then with an acid solution, in the autoclave with an aromatic alcohol having a high boiling point; it has also been proposed to treat them in presence of hydrolyzing agents, in an alkaline solution to which a saponifiable substance is subsequently added, in an oxidizing caustic solution, in an aqueous solution of glycerine, in a bath to which saponified oil or fatty acid has been added.

Among these processes, certain of them cannot be used industrially on account of the very high cost, others destroy the fibre, or, at least spoil it, and finally others do not give any improvement over the standard process.

The present invention relates to a process for the cold retting of coconuts, consisting in soaking th coconuts, which may or may not be previously crushed, in a bath having a pH value greater than 7, and the capillary constant of which is slightly below that of pure water at the same temperature. Substances giving rise to the Brownian movement as will be explained below, are preferably added to the soaking bath.

According to this invention the coconuts are treated in a bath having a slight induced superficial tension, which means that it will be sufficient to create the capillary constant that is slightly below that of pure water at the temperature considered; the action thus set up is of catalytic character.

For that purpose a certain amount of alcohol may be admixed with the soaking bath, excellent results are thus obtained by adding a proportion of ethyl alcohol of the order of 5 parts in 10,000.

The capillary constant of water at 20 C. being 53 dynes per cm. the capillary constant e. g. of ethyl alcohol at the same temperature is 22.03

Alcohol acts as a positive catalyser, which explains why a small amount is sufiicient to obtain a capillary constant :c that is lower than the capillary constant y of pure water; the dilference (at-y) must be of difierential order of magnitude.

Alcohols that may advantageously be used are those of the fatty series or their homologue compounds, either alone or in mixtures, such as ethyl alcohol as already mentioned, propyl, butyl; amyl, caproic alcohols and the like; or also polyalcohols saturated or unsaturated alcohols and acyclic alcohols.

Moreover, considering the stagnancy of the baths, and to avoid high equipment costs, a constant effort of disintegration has to be exerted on the mesocarp constituents as a whole; a disintegrating power which is useful on the parenchyma but which has no ffect on the fibre to be extracted.

For that purpose, the Brownian movement is started in the soaking bath by the addition to the same, after alcoholization, of a sulfonated vegetable oil neutralized in a caustic medium complemented with an ammoniacal medium and loaded with sodium, ammonium or potassium sulphate; the alcohol acts as a connection between the apparent rough emulsion and the fine emulsion initially visible.

It is important to remark that all these actions, be they of chemical or physical character or both, make it essentially necessary to use .a medium giving a pH value higher than '7; which radically distinguishes the method according to the invention from previous methods operating in baths having an acid reaction.

According to the invention the coconut is let to stay in an anticryptogamic bath, which, inversely to retting by prolonged immersion in stagnant water, avoids any putrescible formation and moreover allows to treat the fibre without further rising as a result of the absence of germs, the bath could be anticryptogamic by its own composition; its anticryptogamic power could be enhanced by the addition of products having an antiseptic function.

The extremely soft action of the treatment baths gives an exceptional value to the process in that the fibre to be extracted, which is embedded in the mass of the mesocarp constituents, is submitted just as well as the parenchymous substances to physico-chemical phenomena.

A kind of osmotic pressure producing the swelling of the fibre causes the softening of the substances to be eliminated.

By the above described process a satisfactory retting is already obtained in the cold after some hours. At the end of a period which depends on the nature of the nuts treated, on their age and on the surrounding temperature, and which, in some cases, will be 24 hours and even less, this retting treatment is of such a kind as to permit an easy mechanical treatment of the fibre.

One of the main advantages of this retting process resides in that it allows the thin as well as the medium and coarse fibres to be kept unaltered, while by the slow retting process the destructive action is exerted not only on the :parenchymous materials but also on the thin peripheral fibres which consequently are lost at least partially.

The fibres obtained by the process according to this invention display apparent characteristics, namely their color, dynamometric coefiicient, elasticity, strength, adhesive power, etc, which allow them to be distinguished from fibres obtained by prior methods, and these differences give an increased intrinsical value to the flock.

I claim:

1. .A process for retting coconut fibres consist- 2. A process for retting coconut fibres consisting in immersing said fibres in an aqueous bath substantially at the surrounding temperature and having a pH value greater than 7, said bath containing ethyl alcohol in a quanttiy suitable for lowering to the extent of a few hundredths the unit of superficial tension of the water.

3. A process for retting coconut fibres consisting in immersing said fibres in a bath substantially at the surrounding temperature, containing water, a substance which raises the pH of the bath to a value greater than 7, and any alcohol capable of lowering the superficial tension of the Water below 53 dynes per centimeter.

4. A process for retting coconut fibres as claimed in claim 3, in which said bath moreover contains a sulphonated vegetable oil which has ing in immersing said fibres in an aqueous bath substantially at the surrounding temperature and having a pH value greater than '7, said bath containing an alcohol of the fatty series suitable for lowering to the extent of a few hundredths the unit of superficial tension of the water.

been incompletely neutralized in caustic soda, said neutralization being completed by ammonia.

BERNARD MAISANT. 

